1. Field of the Invention
This invention relates to strip chart recorders and more particularly to a fixed thermal printhead solid state chart recorder for thermal recording on heat sensitive paper.
2. Description of the Prior Art
In the prior art, strip chart recorders have been comprised of slide wires and servos in combination with pens and ink. The reliability and useful life of such recorders was limited.
More recently, movable head thermal printers have been employed for strip chart recording. These devices avoided the pens, pen motors and linkages necessary to implement the earlier recorders. An example of a thermal recorder capable of printing annotated traces is described and claimed in U.S. Pat. No. 3,840,878, issued on Oct. 8, 1974, entitled "Dual Mode Thermal Recorder" assigned to the assignee of this invention. A disadvantage of the dual mode thermal recorder is that not only is the paper moved, but the printhead is moved as well.
The invention described herein overcomes the disadvantages mentioned above. There are no pens, pen motors and linkages, or slidewires. Also, the printhead is fixed so that the only moving component is the chart drive system.